Originally Posted by
SoFloGuy 
I think you are right, but at the same time I think that they wouldn't know if they had it. Telling them might even be worse. Most desserts call for vanilla extract and that alcohol flavoring does get lost in most recipes.
Telling them would not be worse. It really is their decision to make. If you didn't tell them and they were to have a reaction to it, how would that make you feel? It is best to be honest and tell them.